Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the genotoxic effects of three different brands and three types of coffee (freshly brewed regular, instant regular and freshly brewed decaffeinated) in two mammalian systems: the Chinese hamster ovary (CHO) AUXB1 cell line and human peripheral lymphocytes. Sister-chromatid exchanges (SCEs) and endoreduplicated cells (ERCs) were used as the endpoints. Coffee was prepared according to the manufacturer's suggestions, and after cooling, administered to cultured cells at dilutions ranging up to 11% that of full-strength coffee. Each brand and type of coffee induced significant levels of SCEs and ERCs in AUXB1 cells. SCEs, but not ERCs, were induced in human peripheral lymphocytes. Bisulfite, which complexes with carbonyls and reduces their genotoxicity, significantly diminished the number of SCEs and ERCs found after administration of coffee. Catalase and peroxidase, enzymes that destroy hydrogen peroxide activity, had no significant effect upon the SCE and ERC frequencies in AUXB1 cultures treated with freshly brewed regular coffee. These experiments indicate that different brands and types of coffee have sufficient genotoxic activity to increase SCEs and ERCs at levels only a fraction of those normally consumed. 1,2-Dicarbonyls alone and peroxides alone do not appear to be responsible for the majority of SCEs and ERCs that were observed to be induced by dilute coffee.
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PMID:Cytogenetic response to coffee in Chinese hamster ovary AUXB1 cells and human peripheral lymphocytes. 268 27

The enzymes involved in antioxidative activity and the cellular content of the antioxidants glutathione and ascorbate in the cyanobacteria Nostoc muscorum 7119 and Synechococcus 6311 have been examined for their roles in hydroperoxide removal. High activities of ascorbate peroxidase and catalase were found in vegetative cells of both species and in the heterocysts of N. muscorum. The affinity of ascorbate peroxidase for H2O2 was 15- to 25-fold higher than that of catalase. Increased activity of ascorbate peroxidase was observed in N. muscorum when H2O2 production was enhanced by photorespiration. Catalase activity was decreased in dilute cultures whereas ascorbate peroxidase activity increased. Ascorbate peroxidase activity also increased when the CO2 concentration was reduced. Ascorbate peroxidase appears to be a key enzyme in a cascade of reactions regenerating antioxidants. Dehydroascorbate reductase was found to regenerate ascorbate, and glutathione reductase recycled glutathione. In vegetative cells glutathione was present in high amounts (2-4 mM) whereas the ascorbate content was almost 100-fold lower (20-100 microM). Glutathione peroxidase was not detected in either cyanobacterium. It is concluded from the high activity of ascorbate peroxidase activity and the levels of antioxidants found that this enzyme can effectively remove low concentrations of peroxides. Catalase may remove H2O2 produced under photooxidative conditions where the peroxide concentration is higher.
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PMID:Hydroperoxide metabolism in cyanobacteria. 308 78